Projector

• US 6,529,250 B1
• Filed: 05/21/1998
• Issued: 03/04/2003
• Est. Priority Date: 05/22/1997
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Murakami, Osamu, Yajima, Akitaka, Itoh, Yoshitaka
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): NGUYEN, DUNG T
• Application Number:
  US09/082,534
• Time in Patent Office: 1,748 Days
• Field of Search: 349/5, 349/96, 353/38, 353/20, 353/31
• US Class Current: 349/5
• CPC Class Codes: G02B 27/1046 for use with transmissive spatial light modulators
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02B 27/149 using crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence

Abstract

A projection-type display apparatus of the invention aiming at solving the problem of heat generation caused by absorption of light by a polarizing means of a liquid crystal light valve. To overcome this problem, the projection-type display apparatus of the invention includes a light source, a light valve for modulating the light from the light source, and a projection optical means for projecting the light modulated by the light valve, with the light valve including a liquid crystal panel and a polarizing means, provided on the light source side of the liquid crystal panel, and the polarizing means being formed of a multi-layered film which primarily transmits one of two types of polarization axis component light beams and primarily reflects the other of the two types of polarization axis component light beams.

Claims

1. A projector, comprising:

an illumination optical system including a light source and a polarization converter;

a colored-light separator that separates light beam from the illumination optical system into a plurality of colored light beams;

a plurality of light valves that modulate the colored light beams separated by the colored-light separator, each of the light valves including a liquid crystal panel and a reflective polarizer provided on a light-incident side of an associated liquid crystal panel, the reflective polarizer transmitting one of a first polarized light and a second polarized light among incident light beam and reflecting the other of the first polarized light and the second polarized light among the incident light beam;

a synthesizing optical element that synthesizes the light beams modulated by the plurality of light valves; and

a projection optical system that projects the light beam synthesized by the synthesizing optical element,

the polarization converter, provided between the light source and the colored-light separator, aligning at least most of the light beam from the light source with light beam capable of transmitting through the reflective polarizer, and emitting light beam including the aligned light beam toward the reflective polarizer through the colored-light separator,

the reflective polarizer transmitting most of the incident light beam emitted from the polarization converter so as to enter the liquid crystal panel and reflecting small amount of light among the incident light beam so as to return toward the illumination optical system as a reflected light, and

the illumination optical system further including a collimating optical element, the collimating optical element being provided between the light source and the reflective polarizer and substantially collimating the light from the light source.

2. The projector according to claim 1, the illumination optical system including a reflecting mirror that reflects the reflected light which has returned through the colored-light separator as substantially collimated light which leaves the reflecting mirror.

3. The projector according to claim 1, the illumination optical system including a reflecting mirror that reflects the reflected light which has returned through said the colored-light separator, and a condenser lens that condenses and collimates the light from the reflecting mirror into substantially collimated light.

4. The projector according to claim 1, the reflective polarizer having a wavelength selective transmission characteristic set to reflect an infrared component and/or an ultraviolet component.

5. The projector according to claim 1, the reflective polarizer being either adhered to or bonded to the substrate of the liquid crystal panel associated thereto.

6. The projector according to claim 1, the reflected light reflected by the reflective polarizer being reflected by the illumination optical system so as to be included in the incident light beam on the reflective polarizer.

7. The projector according to claim 6, the reflected light reflected by the reflective polarizer being reflected by a reflector of the light source or by the polarization converter.

8. A projector, comprising:

an illumination optical system including a light source and a polarization converter;

a light valve that modulates light from the illumination optical system; and

a projection optical system that projects the light modulated by the light valve,

the light valve including a liquid crystal panel and a reflective polarizer provided on a light-incident side of the liquid crystal panel, the reflective polarizer transmitting a first polarized component among incident light and reflecting a second polarized component among the incident light,

the polarization converter, provided between the light source and the reflective polarizer, aligning at least most of the light from the light source with light capable of transmitting through the reflective polarizer, and emitting light including the aligned light toward the reflective polarizer,

the reflective polarizer transmitting most of the incident light emitted from the polarization converter so as to enter the liquid crystal panel and reflecting the second polarized component among the incident light so as to return toward the illumination optical system as a reflected light, and

the illumination optical system further including a collimating optical element, the collimating optical element being provided between the light source and the reflective polarizer and substantially collimating the light from the light source.

9. The projector according to claim 8,

the light valve further comprising a second reflective polarizer provided on a light-emitting side of the liquid crystal panel,

the second reflective polarizer transmitting one of the first polarized component and the second polarized component and reflecting the other of the first polarized component and the second polarized component so that the reflected light returns toward the illumination optical system.

10. The projector according to claim 8, the reflective polarizer being either adhered to or bonded to the substrate of the liquid crystal panel.

11. The projector according to claim 8, the reflected light reflected by the reflective polarizer being reflected by the illumination optical system so as to be included in the incident light on the reflective polarizer.

12. The projector according to claim 11, the reflected light reflected by the reflective polarizer being reflected by a reflector of the light source or by the polarization converter.

13. A projector, comprising:

an illumination optical system including a light source lamp, a reflective polarizer, a ¼

wavelength plate and a reflector;

a colored-light separator that separates light beam from the illumination optical system into a plurality of colored light beams;

a plurality of light valves that modulate the colored light beams separated by the colored-light separator;

a synthesizing optical element that synthesizes the light beams modulated by the plurality of light valves;

a projection optical system that projects the light beam synthesized by the synthesizing optical element; and

a condenser lens, provided between the reflector and the reflective polarizer, that condenses and collimates the light reflected by the reflector as substantially collimated light,

the reflective polarizer, provided between the light source lamp and the colored-light separator, being formed of a multi-layered film that transmits a first polarized light among incident light beam so as to enter the colored-light separator and reflects a second polarized light among the incident light beam as a reflected light,

the ¼

wavelength plate being provided between the light source lamp and the reflective polarizer,

the reflector being provided behind the light source lamp on opposite side of the ¼

wavelength plate, and

the reflected light reflected by the reflective polarizer being returned toward the reflector through the ¼

wavelength plate, reflected by the reflector, reentered the ¼

wavelength plate, and converted by the ¼

wavelength plate so that the reflected light are capable of transmitting the reflective polarizer and entering the colored-light separator,

the colored light beam which enters the first films and the second films, and

a plurality of the multi-layered films of the light valves having different thickness from each other.

14. The projector according to claim 13, the reflective polarizer having a wavelength selective transmission characteristic set to not allow transmission of an infrared component and/or an ultraviolet component.

15. The projector according to claim 13, further comprising a second reflective polarizer, provided between the colored-light separator and a liquid crystal panel of the light valve, that transmits most of the light beam emitted from the colored-light separator so as to enter the liquid crystal panel.

16. The projector according to claim 13, the light valves including a light-emitting side reflective polarizer provided on a light-emitting side of the light valve associated thereto,

the light-emitting side reflective polarizer transmitting one of the first polarized light and the second polarized light and reflecting the other of the first polarized light and the second polarized light.

17. A The projector according to claim 13, further comprising:

a first lens plate, provided between the light source lamp and the reflective polarizer, that has a plurality of rectangular lenses; and

a second lens plate, provided between the first lens plate and the light valves, that irradiates the light beam emitted from each of the rectangular lenses, the first lens plate holding the ¼

wavelength plate.

18. The projector according to claim 13, further comprising:

a first lens plate, provided between the light source lamp and the reflective polarizer, that has a plurality of rectangular lenses; and

a second lens plate, provided between the first lens plate and the colored-light separator, that irradiates the light beam emitted from each of the rectangular lenses, the second lens plate holding the reflective polarizer.

19. A projector, comprising:

an illumination optical system including a light source and a polarization converter;

a light valve that modulates light from the illumination optical system, the light valve including a liquid crystal panel having a plurality of pixels, a first polarizer provided on a light-incident side of the liquid crystal panel, and a second polarizer provided on a light-emitting side of the liquid crystal panel, the first polarizer transmitting a first polarized light among incident light, the second polarizer transmitting one of the first polarized light and a second polarized light among incident light and reflecting the other of the first polarized light and the second polarized light among the incident light; and

a projection optical system that projects the light modulated by the light valve,

the polarization converter, provided between the light source and the first polarizer, aligning at least most of light from the light source with light capable of transmitting through the first polarizer, and emitting light including the aligned light toward the first polarizer,

the first polarizer transmitting most of the incident light emitted from the polarization converter so as to enter the liquid crystal panel,

the liquid crystal panel modulating the light transmitted through the first polarizer by the pixels and transmitting the modulated light to the second polarizer,

the second polarizer transmitting a part of the incident light modulated by the pixels of the liquid crystal panel and reflecting the other part of the incident light modulated by the pixels of the liquid crystal panel as a reflected light,

the reflected light reflected by the second polarizer being transmitted through the pixels of the liquid crystal panel toward the illumination optical system, and

the illumination optical system further including a collimating optical element, the collimating optical element being provided between the light source and the reflective polarizer and substantially collimating the light from the light source.

20. The projector according to claim 19, the first polarizer transmitting the first polarized light and reflecting the second polarized light.

21. The projector according to claim 19, the reflected light reflected by the second polarizer being reflected by the illumination optical system so as to be included in the incident light on the first polarizer.

22. The projector according to claim 21, the reflected light reflected by the second polarizer being reflected by a reflector of the light source or by the polarization converter.